This invention relates to apparatus for destroying information recorded on a compact disc so as to prevent its reproduction. More particularly, the invention is concerned with apparatus for defacing compact discs to render them unplayable, without cracking or destroying the disc substrate.
As is well known, the compact disc is an increasingly popular medium for the replication of audio programs. As currently manufactured, the compact disc comprises a thin circular polycarbonate substrate approximately 43/4 inches in diameter having a central aperture adapted to be received on the centering mechanism of a disc player. Usually, the disc has digitally encoded information on one surface thereof which is adapted to be laser-read by the disc player. The information-bearing surface of the substrate is coated with a thin film of aluminum which, in turn, is covered with a protective lacquer coating, of which two types are currently in common use. One is a cellulose nitrate based material in a suitable solvent such as toluene, and the other is an ultraviolet cured acrylic based material. Information regarding the programs recorded on the disc is printed in ink on the lacquer coating.
In the course of manufacture and distribution of such compact discs, many may be scrapped as production rejects, or may be returned to the manufacturer as a consequence of inventory obsolescence or other reasons. This presents a serious problem of disposal, as well as a problem of insuring that such discs, particularly the returns, are not re-introduced into the channels of commerce through theft, for example, while awaiting disposal. The illicit distribution of recorded information is widespread in the entertainment industry, and very large revenues would be lost by a record company through the unauthorized distribution of such returned discs, to say nothing of the damage to its reputation should production rejects find their way into distribution channels.
While these problems could be solved by cracking, crushing or otherwise destroying the mechanical integrity of returned or rejected discs and discarding the resulting waste product in a landfill, the polycarbonate discs, provided the coatings are removed, have sufficiently high scrap value as to justify removal of the coatings to reclaim the polycarbonate, which is best done if the disc is unbroken. However, removal of the coatings is preferably done by a batch process, which may result in temporary accumulation of discs in sufficient numbers to be attractive to a thief.
A primary object of the present is to provide a means for defacing at least the information-bearing surface of a compact disc to render it unplayable.
Another object of the invention is to provide means for rendering a compact disc unplayable without cracking or destroying the polycarbonate substrate.
Still another object of the invention is to provide apparatus for defacing compact discs with identifiable markings for facilitating determination of the source of defaced discs that may illicitly find their way into distribution channels.